In order to evaluate the environmental effect of three different systems of managing a continuous crop of maize, the residues of the active ingredients of herbicides (terbuthylazine, metolachlor and dicamba) in the soil and grain were investigated in an experiment begun in 1990 and still in course. The three cultivation systems were characterized by different chemical and mechanical inputs and corresponded to three diverse approaches to chemical weed control: the “conventional” system (terbuthylazine + metolachlor in pre-emergence), the “reduced input” system (nicosulfuron + dicamba in post-emergence), and the “strip-cultivation” system (terbuthylazine + metolachlor in pre-emergence, but restricted to a strip centred on the maize row). Soil sampling was carried out on the 26th March (2 days before the soil was tilled), the 30th June (45 days after pre-emergence herbicide treatment) and on the 17th November; grain analysis was carried out at harvest. The results show that at no point was any herbicide residue found on the grains of maize. On the other hand, in the soil, the residue concentrations observed depended on the cultivation system used (active ingredient, soil tillage, fertilization rate, ect). The greatest ecotoxic risks were however associated with the conventional system, while there seemed no cause for worry from an environmental point of view with the adoption of the reduced-input system.
|Titolo:||Soil and grain herbicide residues as influenced by different management systems in a continuous maize cropping|
|Anno del prodotto:||2003|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|